I have recently had some water flood my basement bathroom.I tore out the old shower and surround and cleaned every thing up. The existing drain for the shower is cast iron and is about one inch below the concrete floor surface.I am wondering what is the best way to connect the new abs shower drain to the cast iron and have a watertight installation.

I have recently had some water flood my basement bathroom.I tore out the old shower and surround and cleaned every thing up. The existing drain for the shower is cast iron and is about one inch below the concrete floor surface.I am wondering what is the best way to connect the new abs shower drain to the cast iron and have a watertight installation.
The easiest way would be to cut the cast iron trap raiser back and convert to ABS using a shielded coupling,(see image). You now have a ABS raiser that you may glue the shower drain to. Good luck, Tom

I was thinking about using one of those fittings,I have used similar ones in other applications. However there is no pipe above the concrete floor to attach to. The cast iron is 1" below the surface and completely surrounded by concrete.Would I have to chip out the concrete to be able to flange around the pipe or is there anting that will transition to the inside of the cast iron.

You are not telling us whether you plan on installing new Plastic Shower Pan or you are going to build one yourself.

If you plan on buying new plastic pan, than you buy the type the has so-called "No Caulk" drain. Drain itself is about 2-3" deep. You put down your new shower pan in its place. Drain opening will line up with existing Cast Iron drain. You then proceed with installing the " deep. You put down your new shower pan in its place. Drain opening will line up with existing Cast Iron drain. You then proceed with installing the " drain from the above. Follow the instructions supplied with the drain.

If you plan on building your own pan ( hot mop or PVC liner ), than you install Cast Iron drain right over that pipe first. The drain is deeper and will comfortably reach your drain pipe. Proceed with making and finishing the pan.

This issue has been discussed here several times. See if you can go back and look it up.

Thanks for the replys. I am using the existing plastic shower pan. I have decided to pour a 3" high concrete base for the shower and have figured out that the drain pipe slides into the cast iron pipe. I think I should be okay.

I have figured out that the drain pipe slides into the cast iron pipe
That sentence bothers me. You just don't "slip" a pipe in, you connect them. That was what you meant wasn't it? Cheers, Tom